The Role of the Acute Octreotide Suppression Test in Detecting Patients with Neuroendocrine Neoplasms.

BACKGROUND: Serum chromogranin A (CgA) is routinely used as a biomarker in patients with neuroendocrine neoplasms (NENs). Several conditions and comorbidities may be associated with falsely elevated CgA, often leading to extensive diagnostic evaluation, which may be costly and harmful. The aim of this study was to analyze the effectiveness of the acute octreotide suppression test (AOST) in differentiating falsely elevated serum CgA. METHODS: Our prospective study enrolled 45 patients from two different patient cohorts: (1) 29 patients with suspicion or presence of NENs (extensive workup and subsequent biopsy confirmed 16 NENs); (2) 16 consecutive patients admitted via the Emergency Department without NENs (non-NENs). AOST was performed after an overnight fast. Baseline CgA was measured, after which 0.25 mg of octreotide was administered subcutaneously. CgA was measured 3 and 6 h after administration. RESULTS: Baseline CgA levels were similar in NENs and non-NENs. At the end of the AOST, CgA decreased by a median of 83.3% (41.0-127.4) in non-NENs and 13.8% (0.0-43.6) in NENs (p < 0.001). In patients with increased baseline CgA, a decrease in CgA at the 6th hour of < 51.3% had 90.0% sensitivity and 88.9% specificity in detecting NENs. In patients with normal baseline serum CgA, a decrease in CgA at the 3rd hour of < 17.6% had 83.3% sensitivity and 81.8% specificity in detecting patients with NENs. The diagnostic accuracy of the AOST in the entire study population was 86.7%. CONCLUSIONS: AOST is a promising tool to increase the diagnostic accuracy of serum CgA.

Genome-wide association study of anthropometric traits in Korcula Island, Croatia.

AIM: To identify genetic variants underlying six anthropometric traits: body height, body weight, body mass index, brachial circumference, waist circumference, and hip circumference, using a genome-wide association study. METHODS: The study was carried out in the isolated population of the island of Korcula, Croatia, with 898 adult examinees who participated in the larger DNA-based genetic epidemiological study in 2007. Anthropometric measurements followed standard internationally accepted procedures. Examinees were genotyped using HumanHap 370CNV chip by Illumina, with a genome-wide scan containing 316730 single nucleotide polymorphisms (SNP). RESULTS: A total of 11 SNPs were associated with the investigated traits at the level of P<10(-5), with one SNP (rs7792939 in gene zinc finger protein 498, ZNF498) associated with body weight, hip circumference, and brachial circumference (P=3.59-5.73 x 10(-6)), and another one (rs157350 in gene delta-sarcoglycan, SGCD) with both brachial and hip circumference (P=3.70-6.08 x 10(-6). Variants in CRIM1, a gene regulating delivery of bone morphogenetic proteins to the cell surface, and ITGA1, involved in the regulation of mesenchymal stem cell proliferation and cartilage production, were also associated with brachial circumference (P=7.82 and 9.68 x 10(-6), respectively) and represent interesting functional candidates. Other associations involved those between genes SEZ6L2 and MAX and waist circumference, XTP6 and brachial circumference, and AMPA1/GRIA1 and height. CONCLUSION: Although the study was underpowered for the reported associations to reach formal threshold of genome-wide significance under the assumption of independent multiple testing, the consistency of association between the 2 variants and a set of anthropometric traits makes CRIM1 and ITGA1 highly interesting for further replication and functional follow-up. Increased linkage disequilibrium between the used markers in an isolated population makes the formal significance threshold overly stringent, and changed allele frequencies in isolate population may contribute to identifying variants that would not be easily identified in large outbred populations.